Common intermediates and kinetics, but different energetics, in the assembly of SNARE proteins

Sylvain Zorman (1, 2) , Aleksander A. Rebane (2) , Lu Ma (1) , Guangcan Yang (1) , Matthew A. Molski (1, 2) , Jeff Coleman (1, 2) , Frederic Pincet (3, 1, 2) , James E Rothman (1, 2) , Yongli Zhang (1, 2)

1 YSM - Yale School of Medicine [New Haven, Connecticut]
2 Yale University [New Haven]
3 LPS - Laboratoire de Physique Statistique de l'ENS

Soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) are evolutionarily conserved machines that couple their folding/assembly to membrane fusion. However, it is unclear how these processes are regulated and function. To determine these mechanisms, we characterized the folding energy and kinetics of four representative SNARE complexes at a single-molecule level using high-resolution optical tweezers. We found that all SNARE complexes assemble by the same step-wise zippering mechanism: slow N-terminal domain (NTD) association, a pause in a force-dependent half-zippered intermediate, and fast C-terminal domain (CTD) zippering. The energy release from CTD zippering differs for yeast (13 kBT) and neuronal SNARE complexes (27 kBT), and is concentrated at the C-terminal part of CTD zippering. Thus, SNARE complexes share a conserved zippering pathway and polarized energy release to efficiently drive membrane fusion, but generate different amounts of zippering energy to regulate fusion kinetics.

Domaines: Sciences du Vivant [q-bio]

Sylvain Zorman, Aleksander A. Rebane, Lu Ma, Guangcan Yang, Matthew A. Molski, et al.. Common intermediates and kinetics, but different energetics, in the assembly of SNARE proteins. eLife, 2014, 3, pp.e03348. ⟨10.7554/eLife.03348⟩. ⟨hal-01316702⟩